THE NEPHRIDIA OF THE POLYCH^TA. 703 



cantrainii, in whicli the communication between tlie two 

 organs has taken place, and the ripe spermatozoa are seen to 

 have passed down into the nephridial canal. 



As already mentioned above, several observers have de- 

 scribed the excretory organs of the Alciopids. Hering long 

 ago (18) gave a brief description of these structures, which 

 he has since corrected and enlarged in a paper published in 

 1892, to which I shall presently refer (19). Claparede, in 

 the supplement to his classical work on the 'Annelids of 

 Naples' (2), confirmed most of Hering's early observations, 

 and gave detailed descriptions and figures of the nephridia 

 and genital funnels in Alciope cantrainii and Asterope 

 Candida. 



Concerning the former he says, p. 106 : 



" Les organes segmentaires ont une forme tres remarquable. 

 La premiere paire est placee an second segment setigere, et, 

 jusqu'au 16'^^^ leur conformation reste identique. Ce sent de 

 longs boyaux cilies dont I'ouverture extreme est placee a la 

 base des pieds du cote ventral. Le boyau se dirige d'abord 

 en dedans, perpendiculairement a I'axe, puis il forme un 

 angle droit, et finit par s'elargir en un petit entonnoir qui 

 s'engage dans le dissepiment separant la cavite du segment 

 de celle du segment precedent. L'entonnoir s'ouvre done 

 dans la cavite du segment precedent. . . . Mais a partir du 

 IG'"® segment setigere Fappareil se complique, chez le male, 

 d'une grosse vesicule piriforme, dont le court pedoncule 

 tubulaire s'insere sur le boyau de I'organe segmentaire. . . . 

 Au temps de la maturite cette vesicule est remplie de zoo- 

 spermes, et joue par consequent le role de vesicule senii- 

 nale." 



Claparede's account is, therefore, nearly correct. He saw 

 the nephridium, alone in the anterior segments, associated 

 with the genital funnels in the segments behind the sixteenth. 

 He failed to find the internal opening of the genital funnel 

 (vesicule seminale), but saw its posterior communication with 

 the nephridial canal. He missed, however, the true anterior 

 extremity of the nephridium, with its solenocytes, and, misled 



